Abstract:

Diarrheaisthe second leading cause of death in under-fives in the world. EHEC 0157:H7 is an important
etiologicagent of diarrhea with public health significance since exposure to low doses can lead to an
infectionand could cause an epidemic. EHEC 0157:H7 induces HUS, the leading cause of acute renal
failurein childrenbelow five years. The global prevalence of EHEC 0157:H7 is about 2% while most
isolatesof this bacterium exhibit multi-drug resistance to most antibiotics in use. To clarify the role of
0157:H7as an important etiologic agent of acute gastroenteritis in children below five years in Kenya, a
descriptivecross-sectional study was conducted to establish the prevalence and antibiotic susceptibility
patternsassociatedwith EHEC 0157 :H7 isolates from human sources. Diarrhea accounted for 7% of all
illnessescausingout-patient morbidity and mortality in children below five years in the study area during
the study period. Stool samples were obtained from 302 consenting children below five years in Embu
Districtwho were systematically selected between November 2009 and June 2010 and characterized as
EHEC0151:H7 using Cowan method as well as sero-typing. Confirmation was through analytical profile
indexingas well as CerTest. Antibiotic susceptibility testing of the isolates was through Kirby Bauer disc
diffusionmethod. 201 (66.7%) samples out of 302, had E. coli, 84 (27.8%) cases had parasites while 17
(5.63%)cases did not have any growth. Out of 201stool samples with E. coli, 32 (10.6%) isolates were
foundto be positive for EHEC 0157:H7 on Sorbitol MacConkey agar, 2 (0.66 %) cases were confirmed to
be positivefor EHEC 0157:H7 by CerTest method, while 12 (4%) cases were confirmed positive EHEC
0157:H7by slide agglutination. Based on sere-typing test results, the area under study was found to be
havinga prevalenceof about 4% which is above' the global prevalence. 58% of the 12 confirmed cases of
E. coli were found to be resistant to Trimethoprim/sulfamethoxazole, 50% were resistant to Ampicillin
while 33% of EHEC 0157:H7 isolates were resistant to Chloramphenicol, Tetracycline and
cotrimoxazole. All EHEC 0157:H7 isolates were susceptible to Streptomycin, Kanamicin and
Gentamicin. Z-test statistic was used to test for significance while a two-tailed chi-square test (X2) was
used to test for associations between various demographic factors. The isolation of EHEC 0157:H7 in
stool samples from children confirms the circulation of this bacterium in the immediate environment
whilethe detection of multidrug resistance is a course for concern. The research findings shall be used to
inform policy on; the need for improvement on provision of clean, safe drinking water and general
hygienefor the general public, the importance of making laboratory confirmations a routine undertaking
in hospitals to ascertain the actual causes of diarrhea particularly in under-fives and state mandating of
cases reporting. Introduction of faster presumptive diagnostic tools such as Rapid-Antigen testing is
highlyrecommended.